Uses for Incomplete Ammonite Sutures: Lateral Lobe and Second Saddle as Markers of Sutural Complexity

Ammonoid sutures are geometric patterns formed by the intersection of septa and shell wall, have long been a diagnostic tool for ammonite researchers such applications as species identification, taxonomic relationships, ontogenetic change, functional evolutionary morphology, determination ecological niche, other aspects ammonoid paleobiology. Researchers interested in variety paleobiological questions related to ammonoids almost always required access entire hemisuture. Without specimens museum or institutional collections, must rely on previously published illustrations photographs sutures. However, due perspective photographs, distortion marginal elements suture geometry occurs curvature near venter umbilicus when photographed profile. The revised approach described here, which we refer Lateral Lobe Saddle, LLS approach, makes use only lateral lobe second saddle S2 (lateral lobe-second pairs, LLS) lie central, mid-whorl undistorted sector line viewed lateral, profile photos illustrations. factors fractal dimension data convert standard hemisuture measurements largely consistent within genera. method’s non-requirement full also facilitates comparisons among an sequence, from multiple taxa where ventral umbilical sutural hidden whorl overlap poor preservation.